System of automatic telephone-exchange.



No. 672,942. Patented Apr. 30, l90l.

AL E. KEITH 8:. J. 8|. C. J. ERlCK-SUN.\ SYSTEM OF AUTOMATIC TELEPHUNE'EXC HANGE.

(Application filed June 23, 1897.) (No Model.) 5 Sheets-Sheet I.

(Application filed June 23, 1897.) (No Model.)

5 Sheets-Sheet 2.

'i l l WITNESSES; E 5.7M

Patented Apr. 30, IBM.

A. E. KEITH & J. &. C. J. ERICKSON. SYSTEM OF AUTOMATIC TELEPHONE EXCHANGE.

(Application filed June 28, 1897. (No Model.) 5 Sheets-6heet 3.

WITNESSES: 6

No. 672,942. PatentedApr. so, |901.. A. E. KEITH & J. & c. J. ERICKSON. SYSTEM OF AUTOMATIC TELEPHONE EXCHANGE.

(Application file d Juz 1e .23, 1897.)

5 Sheets-8heet 4.

(No lllodei.)

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No. 672,942. Patenied Apr. 30, IBM. A. KEITH & J. & c. J. ERICKSON. SYSTEM OF AUTOMATIC TELEPHONE EXCHANGE.

Apphcatxon filed June 23 1897 5 Shegts-Shaet 5.

(No' Model.)

YNGNESSES:

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UNITED STATES PATENT OFFICE.

ALEXANDER E. KEITH, JOHN ERICKSON, AND CHARLES J. ERICKSON, OF

CHICAGO, ILLINOIS,.ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE AU- TOMATIC TELEPHONE EXCHANGE COMPANY, LIMITED, OF BALTIMORE,

MARYLAND SYSTEM OF AUTOMATIC TELEPHONE-EXCHANGE.

SPECIFICATION forming part of Letters Patent No. 672,942, dated April 30, 1901. 7

Application filed June 23, 1897. Serial No. 641,889. (No model.)

To aZZ whom it may concern.-

Be it known that we, ALEXANDER E. KEITH,

JOHN ERIOKSON, and CHARLES J. ERICKSON, citizens of theUnited States, residing at Ohicago, in the county of Cook and State of Iili-.

nois, have invented a new and useful System of Automatic Telephone-Exchange, of which the following is a specification.

Our invention relates to automatic telephone-exchanges; and our object is to reduce the amount of complicated mechanism and the large number of interconnecting Wires usually required at the central station in automatic telephone-exchanges adapted to the. requirements of a large number of patrons,

the same being fully described hereinafter, and is illustrated in the accompanying drawings, in which- Figure 1 is a plan, and Fig. 2 a side elevation looking in the direction indicated by arrow 10, Fig. l, of the switch mechanism of a connector electrical exchange similar 10 what is embodied in our application for patent of the United States, Serial No. 572,331, filed December 16 1895. Fig. 3 is a plan, and Fig. 4 a side elevation looking in the direction indicated by arrow 11, Fig. 3, of a selectorswitch whose operativeinechanism is very similar to what is shown in Figs. 1 and 2;

but there are several particular parts shown in all the above-named figures which specially adapt them to the duty which is described hereinafter. Fig. 5 is a side elevation of the main portion of the operative parts of the selector-switch, showing the side opposite to what is shown in Fig.4. Fig. 6 is a plan of the main portion of the frame of the selector-switch, with the selector-shaft and all the pawls and detents removed to show means for switching and for cutting out the electric current on the frame, for purposes hereinafter fullyd'escribed. Fig. 7 shows, respectively, a plan and an end elevation of the ratchet to permit the selectorshaft in the selector-switch to revolve, in this instance, but one step,.and only one step; but we do not confine ourselves to one step in all instances, since by the addition of more ratchet-teeth to this wheel any required additional number of rotary steps may be four terminal connector-switches with their corresponding connecting-wires, also four seleotor-switches, each being connected with some distant substation with a telephone and signaling-keys. Fig. 9 is a diagrammatic view of a central exchange showing forty selector-switches in four sections of ten each and sixteen connector-switches in four sections of four each, this exchange being shown more extended than in Fig. 8, better to illustrate the system of interconnecting wires.

. Similar characters indicate like parts throughout the several views In each of the connector-switches, Figs. 1 and 2, to the frame A is attached the magnet B, by which lever C is operated to slide shaft D longitudinally by the action of pawl C on ratchet-cylinder E, and to frame A is also attached magnet F, by Which lever G is operated to rotate shaft D by the action of pawl G.

At 12 is a detent serving to hold shaft D in the position it may he slid to longitudinally, and I is a detent for retaining the shaft in some designated position when rotated, both the longitudinal and rotary motions of the shaft being resisted by the resiliency 0f helical spring J, which when the detents and pawls are released causes the shaft to return to the normal position, with the stop-arm K against stop-pin K. v

In Figs. 1 and 2 the connector-switch is shown with a series ofcontact points M, arranged in rows concentric with one connectorshaft D, which is provided with wipers L, which are adaptedby the step-by-step longitudinal and rotary movement'of the shaft to contact one at a time each of the contactpoints'of a particular group of one hundred or less, there being one contact-point in each connector-switch connected electrically with all other similarly disposed and numbered contact points in all the other connectorswitches of the same group of switches.

- In the selector-switch shown in Figs. 3 and 4 the wiper-arms L, 35 L, and 39 L of the shaft D directly contact the switch interconnecting wires N, as shown in United States 100.

Patent No. 540,168, dated May 28, 1895, instead of contacting contact-points directly connected with the wires, as in the connector hereinbefore described; but the principle involved in the use of the interconnecting wires for connecting the several switches of a group is the same in both instances. The wiperarms L, 35 L, and 39 L of the selectorswitches are each insulated from the shaft D and from each other.

The several essential operative parts in both the connectors and selectors in this system are the same, the electrical connections and several of the minor parts, such as cut-outs, being different and are difierently designated by letters.

The magnets in the selectors, Figs. 3 and 4, which serve the same purpose as magnets B in the connectors, Figs. 1 and 2, are lettered B, while the other magnets for rotating the wiper-shafts are lettered F, the wipershafts being lettered Dand the wipers thereof L, 35 L, and 39 L.

The switch interconnecting wires for the connectors are lettered M, and those of the selector-switches are lettered N. The contact-points in the connector-switches are letlered M in Figs. 1 and 2.

This system is adapted to large exchanges, and a portion of an exchange is here shown to illustrate the operation in an exchange having one thousand subscribers. In Fig. 9, at the right hand side of the drawings, are represented four groups 12, 13, 14, and 15, (between the broken lines,) each group having ten selector-switches of the kind shown in Figs. 3 and 4; but in an exchange for one thousand subscribers there are one hundred of such groups. At the left-hand side of Fig. 9 are represented four groups 16, 17, 18, and 19, (between the broken lines,) each group showing only four connector-switches like what is shown in Figs. 1 and 2; but in practice in a system for one thousand subscribers there are ten groups with one hundred switches in a group.

In Fig. 6 each of the selector-switches, which are numbered 20, 21, 22, and 23, represent four of the switches of one of the groups 12, 13, 14, and 15 in Fig. 9, while in Fig. 8 each of the switches numbered 24, 25, 26, and 27 represent one terminal connector-switch in each of the groups 16, 17, 18, and 19 of one hundred each in Fig. 9.

In a system for one thousand subscribers,

' as before stated, there are one hundred groups of ten selector-switches in each group, such as in group 12 13, &c., Fig. 9; also, ten groups of connector switches with one hundred switches in each group 16 17, &c. From each switches in the second group 17 are numbered from 200 to 300, and the third group 18 from 300 to 400, and so on, each group having its particular I] umbered set of switches of one hundred in each group.

The selector-switches correspond with the number of the telephone connected therewith. The function of each of the selectorswitches is to connect with anyone of the ten pairs of interconnecting wires running to the connector-switches.

In this particular system for one thousand subscribers the selector-switches select the hundreds and the connector-switches the tens and unit-s.

Referring to Fig. 8, is shown for selectorswitches 111, 112, 113, and 114, connected with telephones of the same number and their corresponding signal-keys. Fig. 8 shows telephone and selector switch No. 114 connected to telephone, and selector switch No. 111 through connector-switch 27, but telephones Nos. 112 and 113 and the mechanisms ot'their respective selectors are in the normal position.

Referring to diagrammatic view, Fig. 8, to explain the course of the current, should a person at telephone No. 114 call another at telephone No. 111 the circuit is as follows: At station No. 114 press button marked H or Hundreds once,when current. flows from battery 0 through wires Pand Q, magnet B of selector 114, thence through wire R, key H, and wire S to ground, thereby energizing magnet 13, Figs. 3, 4, and 5, and operating pawl C" at the top end of lever C one time against ratchet-teeth E of shaft D and carry shaft D one move longitudinally, after which the signal-key marked T or Ten is pressed once, when current from battery 0 passes through wires P, Q, and W, and through magnet F of selector 114, thence through wire X, spring Y, shaft D, frame A, wire 28, signalkey T, and wire S to ground. The current in passing through magnet F operates armature-lever G and pawl G thereof, which rotates ratchet-wheel I the pitch of one tooth, causing insulated springs 29 and 30 to fall and make connection with contact-point 31 and insulated contact-point 32, Figs. 4 and 5. The U or units button is now pressed once, when the current from battery 0 passes over two courses in part to reach ground, as follows: First, one portion of the current passes from battery 0 through wires Pand 33, then magnet F of connector-switch No. 27, thence through interconnecting wire 34, wiper 35 L of selector-switch 114, thence through wire 36 and spring 30, (which latter are plainly shown in Figs. 3, 4, 6, and 8,) then through contact 32 and wires 37 and R, signal-key U, and wire S to ground. The other branch of the current passes from battery 0 along wires P and Q through magnet B of selector-switch No. 114, thence through wire R, signal-key U, and wire S to ground. After the connection has.been made between springs 29 and 30 the current in passing through magnet F of conhector-switch No.27 energizes the armature of lever G and causes the wiper-shaft D to rotate equal to the pitch of one tooth of ratchetwheel I, which causes the wiper 41 L to connect with interconnecting wire 42 M. After having madthe connection through the selec tor and connector switches the course of the talking-current is as follows: from telephone 114 through wire 28, frameA of selector-switch No. 114, contact 31, spring 29, wire 38, wiper 39 L, then along interconnecting wire 40, frame A of connectorswitch No. 27, and through shaft D, wiper 41 L, interconnecting wire 42 M, wire 43 to normal contact-pin K of selector-switch No. 111, thence along pin K, wiper-shaft D", frame A, and wire 44 to telephone No. 111, thence through wire 45,

magnet B, and wires 46 and P, at which latter point the current divides, part flowing through wires P and Q and magnet B and wire R from selector-switch No. 114 and part flowing through wires 46, P, 33, and magnet F of connector-switch 27 and through interconnecting wire 34,wiper 35 L,wire 36, spring 30, contact 32, wires 37 and R to telephone 114.

Releasing mechanism has been described in the patents hereinbefore referred to, and as this feature is irrelevant in illustrating the salient points of this invention it is omitted.

The particular feature of this'invention is not so much in the particular mechanism employed, but in the grouping of the selector and connector switches and their decimal relations .to each other, which enables one to employ comparatively small switches and few. interconnecting wires to accommodate a large number of patrons.

In a system of one thousand subscribers there are one hundred groups of selectorswitches of ten switches in each group,which are connected direct to the subscribers line. In front of each group of ten selector-switches there are ten pairs of interconnecting wires, such as wires N, Figs, 8 and 9. Each pair of interconnecting Wires connects with one connector-switch, making in all ten connectorswitches,through which any one of the ten se-' lector-switches may make connections. There are one thousand connector-switches, divided into ten groups of one hundred switches in each group, and through each of such groups one hundred subscribers may connect or be connected to.

Referring to Fig. 9, group 12 shows ten selector-switches, in front of which are ten pairs of interconnecting wires, four pairs of which are connected to four different connector-.

hundred connector-switches, but only four are shown, and groups 17, 18, and 19 are similarly represented. Referring again to selec tor-switches in the first group 12, the first pair of interconnecting wires a and a connect with the first of the one hundred connectorswitches 47 in group 16 and the second pair of interconnecting wires 17 and b is connected to the first of lhe one hundred connector-switches 48 in group 17, and so on. c and c and d and d are connected, respectively, Willi the first of the one hundred connector-switches 49 and 50, groups 18 and 19, and so on. The remaining six pairs of interconnecting wiresin selectorgroup 12 connect with the first of the one hundred connectorswitches in the other six groups (not shown) of the ten groups of connectorswitches. In front of the second group of selector-switches 13 are also ten pairs of interconnecting wires, of which the first pair 6 and e is connected with the second of the one hundred connector-switches 51 in group 16, and the second pair of interconnecting wires f and f is connected with the second of the one hundred connectorswitches 52 in group 17, and so on. The third and fourth pairs of interconnecting wires 9 and g and h and h connect, respectively, with the second switches 53 and 54 in groups 1 8 and 19, and so on, and the remaining six pairs of interconnecting wires in selector group 13 connect with the second'of the one hundred con hector-switches in the remaining sixgroups of the ten groups of connectorswitches. In front of the third group of selector-switches 14 are also ten pairs of inter connecting wires, and so on, and before group 15 and before. each of the remaining one hundred groups of ten selector-switches are ten pairs of interconnecting wires, which connect consecutively with the remaining groups of connector-switches, as hereinbefore describedfthat is,the ten pairs of wires in front of the first group of ten selector-switches connect with the first switch in each of the ten groups of one hundred connector-switches, and the ten pairs of wires in front of the second group of ten selector-switches connect with the second switch in each of the ten groups of one hundred connector-switches, and the ten pairs of wires in front of the third group of ten selector-switches connect with the third switch in each of the ten groups, and so on, in the same order, with the remaining groups of selector and connector switches.

It is not always necessary to have ten selector-switches on one group, as a greater or less number may be used.

We claim as our invention 1. The combination with a series of circuits from distant stations, of a seriesof selectors, one for each station, said selectors being arranged in groups, a series of connectors arranged in groups, the connectors of each group forming means of communication with each other, and independent circuits between the selectors and the connectors, the circuits from each group ofselectors forming means of communication with all the groups of connectors and the circuits from each group of connectors forming means of communication with all the groups of selectors,

substantially as set forth.

2. The combination with a series of circuits from distant stations, of a series of selectors, one for each station, said selectors being arranged consecutively in groups, a series of connectors arranged in groups, the connectors of each group forming means of communication With each other, and independent circuits between the selectors and the connectors, the groups of connectors being arranged consecutively to correspond with the consecutive arrangement of the selectors, 

